India’s visa processing center in Canada suspended services Thursday as a rift widened between the countries after Canada’s leader said India may have been involved in the killing of a Canadian citizen.

Ties between Ottawa and New Delhi, two key strategic partners on security and trade, have plunged to their lowest point in years after Canadian Prime Minister Justin Trudeau this week said there were “credible allegations” of Indian involvement in the assassination of a Sikh separatist leader on its soil.

Hardeep Singh Nijjar, a 45-year-old Canadian citizen who had been wanted by India for years, was gunned down in June outside the temple he led in Surrey, outside Vancouver.